1. Field of the Disclosure
The present invention relates to a touch panel and fabricating method thereof. More particularly, the present invention relates to an optical touch panel and fabricating method thereof.
2. Description of Related Art
If a touch panel is integrated into a liquid crystal display (LCD), not only users can conveniently and rapidly implement inputting data, but also accessing function can be interactively provided. Thus, the touch panels are gradually applied into some portable electronic devices such as mobile phones, personal digital assistants (PDA), notebooks or the like.
Currently, the integrating of touch sensing and displaying functions are realized by the technique of embedding photo-sensors into the pixel array of the liquid crystal display device. Specifically, whether the touch event occurs or not is determined by the voltage drop due to the photocurrent which is generated because the embedded photo-sensor is illuminated under light.
FIG. 1A to FIG. 1F are cross-sectional views illustrating a fabricating process of a conventional touch panel. With reference to FIG. 1A, first, a plurality of gate electrodes GE are formed on a substrate 110, and for the sake of convenience of illustration, only one gate electrode GE is shown in FIG. 1A.
Referring to FIG. 1B, on the substrate 110, a first dielectric layer GI, a plurality of channel layers CH and a plurality of ohmic contact layers OC are sequentially formed, wherein the first dielectric layer GI covers the gate electrodes GE and the substrate 110. The channel layers CH and the ohmic contact layers OC are located on the first dielectric layer GI which is corresponding to the gate electrodes GE. The channel layers CH are located between the ohmic contact layers OC and the first dielectric layer GI.
Referring to FIG. 1C, on the substrate 110, a plurality of source electrodes SE, a plurality of drain electrodes DE and a plurality of first electrodes E1 are sequentially formed. Herein the source electrodes SE and the drain electrodes DE are used as a mask when removing a portion of the ohmic contact layers OC such that a plurality of ohmic contact patterns OCP are formed. The source electrodes SE and the drain electrodes DE are respectively located on two opposite sides of the channel layers CH and cover a portion of the channel layers CH. Herein the gate electrodes GE, the channel layers CH, the source electrodes SE and the drain electrodes DE constitute a plurality of read-out transistors T.
Referring to FIG. 1D, a second dielectric layer PV is formed, in order to cover the read-out transistors T, a portion of the first electrodes E1 and a portion of the first dielectric layer GI.
Referring to FIG. 1E, a plurality of photo-sensing layers PS are formed, so as to electrically connected to the first electrodes E1, wherein a portion of the second dielectric layer PV is located between the first electrode E1 and the photo-sensing layers PS.
Referring to FIG. 1F, on the substrate 110, a plurality of second electrodes E2 and a plurality of read-out lines ROL electrically connected to the second electrodes E2 are formed, wherein the second electrodes E2 are respectively located on the corresponding photo-sensing layers PS, and the photo-sensing layers PS are located between the second electrodes E2 and the first electrodes E1. Herein the second electrodes E2, the photo-sensing layers PS and the first electrodes E1 constitute a plurality of photo-sensors S. After the photo-sensors S are formed, the fabrication of the touch panel 100 is initially completed.
In the conventional touch panel 100, since the read-out transistors T and the photo-sensors S do not have display function, color filter layer is not needed to dispose above the read-out transistors T and the photo-sensors S. Accordingly, without having any other layer for protection, in order to avoid the read-out transistors T and the photo-sensors S of the touch panel 100 causing damages due to external environment and human factors, the touch panel 100 is often needed to dispose an extra protective component (e.g., cover plate). Therefore, it may cause the manufacturing cost increased and the complexity of the fabricating process may also be increased.